CA1272690A - High-pressure structure made of rings with peripheral weldments of reduced thickness - Google Patents
High-pressure structure made of rings with peripheral weldments of reduced thicknessInfo
- Publication number
- CA1272690A CA1272690A CA000523550A CA523550A CA1272690A CA 1272690 A CA1272690 A CA 1272690A CA 000523550 A CA000523550 A CA 000523550A CA 523550 A CA523550 A CA 523550A CA 1272690 A CA1272690 A CA 1272690A
- Authority
- CA
- Canada
- Prior art keywords
- shell
- rings
- vessel
- thickness
- weldment
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
Links
Classifications
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16J—PISTONS; CYLINDERS; SEALINGS
- F16J12/00—Pressure vessels in general
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
- B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
- B23K33/00—Specially-profiled edge portions of workpieces for making soldering or welding connections; Filling the seams formed thereby
- B23K33/004—Filling of continuous seams
- B23K33/006—Filling of continuous seams for cylindrical workpieces
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16L—PIPES; JOINTS OR FITTINGS FOR PIPES; SUPPORTS FOR PIPES, CABLES OR PROTECTIVE TUBING; MEANS FOR THERMAL INSULATION IN GENERAL
- F16L13/00—Non-disconnectible pipe-joints, e.g. soldered, adhesive or caulked joints
- F16L13/02—Welded joints
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
- Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10S220/00—Receptacles
- Y10S220/29—Welded seam
Landscapes
- Engineering & Computer Science (AREA)
- General Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Pressure Vessels And Lids Thereof (AREA)
- Filling Or Discharging Of Gas Storage Vessels (AREA)
- Butt Welding And Welding Of Specific Article (AREA)
Abstract
Abstract of the Disclosure A high-pressure structure having a circular cylinder metal shell made of metal rings joined together by weldments and which have peripheral areas of reduced shell thickness at the weldments which permit a reduction in the amount of weld metal deposited while still maintaining sufficient circumferential or hoop stress strength.
Description
This invention relates to circular cylindrical me~al sh~ , e~pecially for high-pressure use~ such as or high~pressure vessels and flow conductors, such as pen-~tocks and bla~t tubes. More particularly, this invention is concerned with an improved high-pres ure structure having a circular cylindrical metal shell made of metal rings joined toge~her by weldments and which have peripheral areas of reduced shell thickne~s at the weld-ments which permit a reduction in the amount of weld metal deposited while still maintaining sufficient cir-cumferential or hoop stress strength.
Background o~ the Invention Circular cylindrical metal shells are widely used in large civi.l engineering projects as, for example, penstocks in dam project~, blast tubes and in the fabri-cation of high-pressure structures, including vessels.
One type of high-pressure vessel which is suit-ably employed in many industriàl processe~ has a circular cylindrical shell body, which is generally positioned hori-zontally or vertically, and end closures which can be hemi-spherical, elliptical or conical shells or even be flat end3. Many pressure vec~els of the described shape are shop fabricated and then transported to the site for erection. ~owever, the large size and weight of some such high-pressure ve~sel3 prohibit~ ~hop fabrication so field fabrication at the ite i~ necessary.
o Whether the high-pressure structure, such as a Ve~9el, i9 9hop or field fabricated, the cylindrical shell is g~nerally made from metal rings which are joined together in con3ecutive order by weldments which connect abutting edge~ of adjacent rings. Because the metal rings often are made of metal plate~ 3 to 12 inche~ or more thick, and have a diameter of 3 to 30 feet or more, the weldments used to join the rings are time consuming and costly to make. Furthermore9 8 inch thick ringq are generally the maximum joined together in field or site fabrication. While vessels greater than 8" thick can be site-erected, vessel construction gets more complicated and therefore more costly for vessels greater than 8" thick.
Some of the complications are:
A. Eight inches (8") is a practical limit for isotope radiation sources for radiographic examination of weldments. Therefore, when the welds are thicker than 8", a linear accelerator must be used for radiography which will require extensive shielding of the area during radio-graphy. This will complicate the completion of these welds making the costs higher and requiring longer schedules.
B. SA-387 Grade 22 Class 2 steel is one of the commonly referenced vessel material~ used in the petroleum refining industry. This material rPquires post weld heat treatm@nt (PWHT) hold time~ which are a function of weld thickness (Table AF-402.1 of ASME Section VIII, Division
Background o~ the Invention Circular cylindrical metal shells are widely used in large civi.l engineering projects as, for example, penstocks in dam project~, blast tubes and in the fabri-cation of high-pressure structures, including vessels.
One type of high-pressure vessel which is suit-ably employed in many industriàl processe~ has a circular cylindrical shell body, which is generally positioned hori-zontally or vertically, and end closures which can be hemi-spherical, elliptical or conical shells or even be flat end3. Many pressure vec~els of the described shape are shop fabricated and then transported to the site for erection. ~owever, the large size and weight of some such high-pressure ve~sel3 prohibit~ ~hop fabrication so field fabrication at the ite i~ necessary.
o Whether the high-pressure structure, such as a Ve~9el, i9 9hop or field fabricated, the cylindrical shell is g~nerally made from metal rings which are joined together in con3ecutive order by weldments which connect abutting edge~ of adjacent rings. Because the metal rings often are made of metal plate~ 3 to 12 inche~ or more thick, and have a diameter of 3 to 30 feet or more, the weldments used to join the rings are time consuming and costly to make. Furthermore9 8 inch thick ringq are generally the maximum joined together in field or site fabrication. While vessels greater than 8" thick can be site-erected, vessel construction gets more complicated and therefore more costly for vessels greater than 8" thick.
Some of the complications are:
A. Eight inches (8") is a practical limit for isotope radiation sources for radiographic examination of weldments. Therefore, when the welds are thicker than 8", a linear accelerator must be used for radiography which will require extensive shielding of the area during radio-graphy. This will complicate the completion of these welds making the costs higher and requiring longer schedules.
B. SA-387 Grade 22 Class 2 steel is one of the commonly referenced vessel material~ used in the petroleum refining industry. This material rPquires post weld heat treatm@nt (PWHT) hold time~ which are a function of weld thickness (Table AF-402.1 of ASME Section VIII, Division
2). As the material gets ~hicker more PWHT time is re-quired and it iB more difficult to provide material that can withstand these long PW~T times and still maintain the specified strength properties after PW~T. Therefore, for ~ ~7~
very thick walled ve~sels, the materials are more expen~ive per unit weight and are also available from fewer sources.
C0 For large site-erected heavy-wall vessels, individual cylindrical section~ of the shell arQ a~sembled on the ground or at a ~hop manufacturing facility and then shipped to the site. These rings are then lifted into place and the girth seams welded together. The time re-quired to complete these girth ~eam weldment3 has a very direct relationship to the construction schedule for heavy-wall vessels. The time and labor to complete the girth seam weldment increases as a quadratic function of the weld thickness. The overall cost and schedule for constructing very thick walled vessels has a negative impact on overall plant costs.
Much of the above discussion also applies to the fabrication o~ metal penstocks, blast tubes and similar large size ~tructures having metal shells which are open-ended.
From the above it is clear that a need exists for improved circular cylindrical metal shells which can be used in high-pres~ure ~tructures, including penstocks, blast tubes and similar open-ended shells, and also as part of thick-walled high-pressure vessels, which can be hop and field fabricated with lower cost~ and in a ~horter time than has been previously po~sible.
Summa ~ of the Invention According to on~ a~peet of the invention there is provided a eircular cylinclrical solid wall~d metal hell ~ 3 with inner and outer surfaces and being capable of with-atanding ~n internal pres.~ure for which the shell is de~igned, the cylindrlcal ~hell comprising a series of con-~ecutive ~etal rings of essentially equal maximum thickness positioned in axial arrangement with abutting end3 of ad-jacent ring~ being joined together by a weldment; and the axial length of the cylindrical shell portion comprising the abutting end portions of adjacent ring~t and the weld-ment joining the abutting end~ together~ having a reduced thickness which i~ not more than about 0090 of the maximum thickness of the rings.
The described circular cylindrical shell can be open or closed at one or both ends. It can be used as a flow conductor, such as a pen~tock, blast tube, or for similar uses.
According to a second aspect of the invention a solid walled hi~h-pressure structure having a circular cy-lindrical shell with inner and outer surfaces and end clo~ure~ and being capable of withstanding an internal pressure for which the structure is designed is provided in which the cylindrical shell comprises a series of con-secutive metal rings of essentially equal maximum thickness positioned in axial arrangement with abutting ends of ad-jacent ring~ being joined together by a weldment and the axial length of the cylindrical shell portion comprising the abutting end portion~ of adjacent rings, and the weld-ment joining the abut~ing ends together t has a reduced thickne~s which i~ not more ~han about 0.90 of the maximum thickness of the rings.
~ 4 --Whether the shell is u3ed as part of a high-pre~ure vessel, or a flow conductor, such as a pen~tock, blast tube or for 30me other use, ths reduced thicknes~ at the joint~, in general~ should not be less than 0.50, and de~ir~bly 0.67, of the maximum thi~kness of the ring~.
An important feature of the invention is that the a~ial length of each ring be 2.5 times the square root o the cylindrical shell internal radius time~ the maximum thicknesR of the cylindrical shell. This sizing of the rings assures that ~he grooves or areas of reduced ~hick-ness are not located too close toge~her to provide the desired shell design strength.
Only the internal surface, or only the external surface, of the cylindrical shell can be a substantially smooth cylindrical surface at the weldment joining abutting ends of adjacent rings. However, the reduced thickness of the axial length of the cylindrical shell can be located radially inward from the outer surface of the shell and radially outward from the inner surface of the shell.
Thu~, the reduced thickness area at the weldment can be located inwardly from both the outer and inner surfaces of the rings and shell~ Furthermore, a shell can be fabri-cated having some of the joints smooth on the inside surface and some joints smooth on the outside surface.
Thus, some of ~he areas of reduced thickness at the weldments can be only inside, and some only outside, the shell D
The area vf reduced thickne~s can define a pe-ripheral groove extending around the outside of the structure, with ~he ~roove haYing a maximum width axial of ~ ~ 7~
the structure adequate to depo~it at least a portion of the weldment from out~ide the 3hell. However, the area of reduced thickne~s can also define a peripheral groove ex-tending around the in~ide of the ~tructure, with the groove having a maximum width axial of the ~tructure adequate to depo~it at least a portion of the weldment ~rom inside the shell. Furthermore, the area of reduced thickness can be defined by peripheral grooves on both sides thereof 50 that one groove i~ on the outside, and another groove is on the in~ide, of the shell.
The shape of the peripheral groove can vary and it can be symmetrical or asymmetrical. It can have a flat or curved bottom when viewed in section parallel to the vessel longitudinal axis and, in addition, the sides of the groove when similarly viewed can be sloped in a curved manner or have tapered surfaces.
Regardless of the particular shape of the groove, the end portion of each ring wall from its thickest part to its thinnest part at the weldment, must be able to with-stand the design maximum circumferential or hoop force for which the veRsel i5 to be used.
By producing a cylindrical shell from metal rings joined together by weldments as described very significant savings in fabrication co~ts are achieved without sacrifice in structur~ stren~th. Since the radial thickness of each weldment is reduced about 0.1 to 0~50 of the maximum 3hell thickness, less welding is needed and this reduces the cost and f~brication time Rubstan~iallyO Additionally, exami nation of weldment quality i5 more readily achieved, ~specially in the field, becau e of the reduced radial thickne~ of the weldment.
The thickness of the rings generally will be in the range of 1 to 20 inches, and usually will be at least 3 inche ~ and de3irably 5 inche~, thick for bcst utilization of the advantages of the invention.
~ y use of the invention, it i5 pos~ible to mor~
r~adily fabricate shell~ for pre~sure v2s~el~, penstock~, bla~t tube~ and the like both in the 3hop and in the field. A~ an example, shell rings 12 inches thick can be joined together conveniently because the weldment~ need only be about 6 to 10.8 inche~ thick at the peripheral groove at each of the weldments.
The use of reduced thickness girth seam weldments can be most easily under~tood by a simplified review of the pressure load on a cylindrical shell. The required thick-ness for the cylinder in the circumferential direction can be approximated as tc = PR/S where;
P = design pressure R = vessel radius S = allowable design stress The re~uired thickness for the longitudinal direction i~ approximated by tl = PR/2S. Therefore the nominal thicknes~ for a cylindrical shell is controlled by the stress in the circumferential direction and is twice the required thicknes~ for the longitudinal direction.
Providing a local area of reduced ~hickne~s ~o 0.67, and even ts just above 0.50, of the maximum shell thicknes will still provide exce~ ~hicknes~ for longi~udinal ~tre~s.
~ S3~`~
The reduced thickness area at the groove will crea~e higher 9tre~5 locally in the circumferential direc~ion. ~owever, ~ince the total amount of material removed i~ small when compared to the remaining material, the ultimate capacity will not be significant~y reduced.
A~ the thinned area trie~ to stretch due to the higher stress, it will be restrained by the thicker material on either side of it. Therefore, some of the pre~sure loading in the thin area will be shifted to the thicker material.
Bursting for ductile material~ will not occur until all the material ha~ fully yielded and is at the ultimate capacity of the material.
Brief Description of the Drawin~s Figure 1 i~ an elevational view of a vertical pressure vessel having a shell fabricated according to the invention;
Figure 2 is an enlarged sectional view of the joint portion circled in Fi~ure 1 before the weldment i9 deposited;
Figure 3 i9 a sectional view of the shell of Figure 1 having the joint area of reduced thickness in the shell external surface;
Figure 4 is a sec~ional view of a shell having a joint with the area of reduced thickness in the shell in~ernal surface;
Figure 5 is a ~ectlonal view of a shell having a join~ in which the area of reduced thickne~ is located radially inward from the ~hell inner and outer ~urface~;
and ~ igure 6 is an elevational view, partially in ~ctlon, o an open-ended shell according to the invention ~uitabl~ for u~e as a penstock, blast tube or the like.
Detailed Description of the Drawin~
To the extent it i~ rea~onable and practical, the ~ame numbers will be used to identiy the same are similar element~.
With reference to Figure 1, the vertical solid walled high-pressure vessel 20 has a vertical shell or body 22, a hemispherical bottom closure 24 and a hemispherical top closure 26. The vessel is supported by legs 28.
The vessel shell or body 22 i~ fabricated from a series of ten consecutive metal rings A to J of essentially eqNal maximum thickness positioned in axial arrangement with abutting ends of adjacent rings being joined together by a weldment 30 (Figure 3)O
The adjacent abutting edges of rings E and F
before weldment 30 is deposited is illustrated by Figure 2. It should be under~tood that all the abutting adjacent edges of all the rings A to J are similarly shaped before welding. The ma~imum width of the area of fully reduced thickness 100 at t~e ~oint i~ 3hown in Figure 2 as W. The maximum depth of the area of reduced thickness 100 i5 ghown in Figure 2 as X. The weldment joining together the abutting ~dge~ of the ring~ E and F will have the thickness Y. X plu~ Y equals the radial thickness Z of rin~s E and F. The thickne s Y, which equal~ the thickne~s of the weldm~nt (Figure 3) has a reduced thickne~ which i~ not g _ , more than about 0.90 of the rin~ thickness Z. ~owever, Y
i9 not les~ than 0.50 of Z. I~ i~ desirabl2 for the edges of the rings E, F to be tapered or curved outwardly from the thin~st portion Y of each ring to the thickest part o~
each ring Z. Thu~, a~ shown in Figures 2 and 3, each ring E, F i~ tapered outwardly 50, 52. As shown in Figure 2, the adjacent abuttin~ edges of rings E and F are beveled 36,38,40,42 to provide space for deposit of weld metal through the full thickness of the joint. Such beveled surface~ can have any suitable shape.
Returning now to Figure 2, the thickness Z of the rings used to fabricate shell 22 may be increased in thick-ness above the thlckne~s V used for rings where the joints are made the full thickness of the r.inys to reinforce the joint area surrounding the area of reduced thiclcnes~.
Thus, Z can be about 1 to 1.2 times the thickness V.
The second embodiment of the invention illus-trated by Figure 4 is similar to that shown in Figures 1 to
very thick walled ve~sels, the materials are more expen~ive per unit weight and are also available from fewer sources.
C0 For large site-erected heavy-wall vessels, individual cylindrical section~ of the shell arQ a~sembled on the ground or at a ~hop manufacturing facility and then shipped to the site. These rings are then lifted into place and the girth seams welded together. The time re-quired to complete these girth ~eam weldment3 has a very direct relationship to the construction schedule for heavy-wall vessels. The time and labor to complete the girth seam weldment increases as a quadratic function of the weld thickness. The overall cost and schedule for constructing very thick walled vessels has a negative impact on overall plant costs.
Much of the above discussion also applies to the fabrication o~ metal penstocks, blast tubes and similar large size ~tructures having metal shells which are open-ended.
From the above it is clear that a need exists for improved circular cylindrical metal shells which can be used in high-pres~ure ~tructures, including penstocks, blast tubes and similar open-ended shells, and also as part of thick-walled high-pressure vessels, which can be hop and field fabricated with lower cost~ and in a ~horter time than has been previously po~sible.
Summa ~ of the Invention According to on~ a~peet of the invention there is provided a eircular cylinclrical solid wall~d metal hell ~ 3 with inner and outer surfaces and being capable of with-atanding ~n internal pres.~ure for which the shell is de~igned, the cylindrlcal ~hell comprising a series of con-~ecutive ~etal rings of essentially equal maximum thickness positioned in axial arrangement with abutting end3 of ad-jacent ring~ being joined together by a weldment; and the axial length of the cylindrical shell portion comprising the abutting end portions of adjacent ring~t and the weld-ment joining the abutting end~ together~ having a reduced thickness which i~ not more than about 0090 of the maximum thickness of the rings.
The described circular cylindrical shell can be open or closed at one or both ends. It can be used as a flow conductor, such as a pen~tock, blast tube, or for similar uses.
According to a second aspect of the invention a solid walled hi~h-pressure structure having a circular cy-lindrical shell with inner and outer surfaces and end clo~ure~ and being capable of withstanding an internal pressure for which the structure is designed is provided in which the cylindrical shell comprises a series of con-secutive metal rings of essentially equal maximum thickness positioned in axial arrangement with abutting ends of ad-jacent ring~ being joined together by a weldment and the axial length of the cylindrical shell portion comprising the abutting end portion~ of adjacent rings, and the weld-ment joining the abut~ing ends together t has a reduced thickne~s which i~ not more ~han about 0.90 of the maximum thickness of the rings.
~ 4 --Whether the shell is u3ed as part of a high-pre~ure vessel, or a flow conductor, such as a pen~tock, blast tube or for 30me other use, ths reduced thicknes~ at the joint~, in general~ should not be less than 0.50, and de~ir~bly 0.67, of the maximum thi~kness of the ring~.
An important feature of the invention is that the a~ial length of each ring be 2.5 times the square root o the cylindrical shell internal radius time~ the maximum thicknesR of the cylindrical shell. This sizing of the rings assures that ~he grooves or areas of reduced ~hick-ness are not located too close toge~her to provide the desired shell design strength.
Only the internal surface, or only the external surface, of the cylindrical shell can be a substantially smooth cylindrical surface at the weldment joining abutting ends of adjacent rings. However, the reduced thickness of the axial length of the cylindrical shell can be located radially inward from the outer surface of the shell and radially outward from the inner surface of the shell.
Thu~, the reduced thickness area at the weldment can be located inwardly from both the outer and inner surfaces of the rings and shell~ Furthermore, a shell can be fabri-cated having some of the joints smooth on the inside surface and some joints smooth on the outside surface.
Thus, some of ~he areas of reduced thickness at the weldments can be only inside, and some only outside, the shell D
The area vf reduced thickne~s can define a pe-ripheral groove extending around the outside of the structure, with ~he ~roove haYing a maximum width axial of ~ ~ 7~
the structure adequate to depo~it at least a portion of the weldment from out~ide the 3hell. However, the area of reduced thickne~s can also define a peripheral groove ex-tending around the in~ide of the ~tructure, with the groove having a maximum width axial of the ~tructure adequate to depo~it at least a portion of the weldment ~rom inside the shell. Furthermore, the area of reduced thickness can be defined by peripheral grooves on both sides thereof 50 that one groove i~ on the outside, and another groove is on the in~ide, of the shell.
The shape of the peripheral groove can vary and it can be symmetrical or asymmetrical. It can have a flat or curved bottom when viewed in section parallel to the vessel longitudinal axis and, in addition, the sides of the groove when similarly viewed can be sloped in a curved manner or have tapered surfaces.
Regardless of the particular shape of the groove, the end portion of each ring wall from its thickest part to its thinnest part at the weldment, must be able to with-stand the design maximum circumferential or hoop force for which the veRsel i5 to be used.
By producing a cylindrical shell from metal rings joined together by weldments as described very significant savings in fabrication co~ts are achieved without sacrifice in structur~ stren~th. Since the radial thickness of each weldment is reduced about 0.1 to 0~50 of the maximum 3hell thickness, less welding is needed and this reduces the cost and f~brication time Rubstan~iallyO Additionally, exami nation of weldment quality i5 more readily achieved, ~specially in the field, becau e of the reduced radial thickne~ of the weldment.
The thickness of the rings generally will be in the range of 1 to 20 inches, and usually will be at least 3 inche ~ and de3irably 5 inche~, thick for bcst utilization of the advantages of the invention.
~ y use of the invention, it i5 pos~ible to mor~
r~adily fabricate shell~ for pre~sure v2s~el~, penstock~, bla~t tube~ and the like both in the 3hop and in the field. A~ an example, shell rings 12 inches thick can be joined together conveniently because the weldment~ need only be about 6 to 10.8 inche~ thick at the peripheral groove at each of the weldments.
The use of reduced thickness girth seam weldments can be most easily under~tood by a simplified review of the pressure load on a cylindrical shell. The required thick-ness for the cylinder in the circumferential direction can be approximated as tc = PR/S where;
P = design pressure R = vessel radius S = allowable design stress The re~uired thickness for the longitudinal direction i~ approximated by tl = PR/2S. Therefore the nominal thicknes~ for a cylindrical shell is controlled by the stress in the circumferential direction and is twice the required thicknes~ for the longitudinal direction.
Providing a local area of reduced ~hickne~s ~o 0.67, and even ts just above 0.50, of the maximum shell thicknes will still provide exce~ ~hicknes~ for longi~udinal ~tre~s.
~ S3~`~
The reduced thickness area at the groove will crea~e higher 9tre~5 locally in the circumferential direc~ion. ~owever, ~ince the total amount of material removed i~ small when compared to the remaining material, the ultimate capacity will not be significant~y reduced.
A~ the thinned area trie~ to stretch due to the higher stress, it will be restrained by the thicker material on either side of it. Therefore, some of the pre~sure loading in the thin area will be shifted to the thicker material.
Bursting for ductile material~ will not occur until all the material ha~ fully yielded and is at the ultimate capacity of the material.
Brief Description of the Drawin~s Figure 1 i~ an elevational view of a vertical pressure vessel having a shell fabricated according to the invention;
Figure 2 is an enlarged sectional view of the joint portion circled in Fi~ure 1 before the weldment i9 deposited;
Figure 3 i9 a sectional view of the shell of Figure 1 having the joint area of reduced thickness in the shell external surface;
Figure 4 is a sec~ional view of a shell having a joint with the area of reduced thickness in the shell in~ernal surface;
Figure 5 is a ~ectlonal view of a shell having a join~ in which the area of reduced thickne~ is located radially inward from the ~hell inner and outer ~urface~;
and ~ igure 6 is an elevational view, partially in ~ctlon, o an open-ended shell according to the invention ~uitabl~ for u~e as a penstock, blast tube or the like.
Detailed Description of the Drawin~
To the extent it i~ rea~onable and practical, the ~ame numbers will be used to identiy the same are similar element~.
With reference to Figure 1, the vertical solid walled high-pressure vessel 20 has a vertical shell or body 22, a hemispherical bottom closure 24 and a hemispherical top closure 26. The vessel is supported by legs 28.
The vessel shell or body 22 i~ fabricated from a series of ten consecutive metal rings A to J of essentially eqNal maximum thickness positioned in axial arrangement with abutting ends of adjacent rings being joined together by a weldment 30 (Figure 3)O
The adjacent abutting edges of rings E and F
before weldment 30 is deposited is illustrated by Figure 2. It should be under~tood that all the abutting adjacent edges of all the rings A to J are similarly shaped before welding. The ma~imum width of the area of fully reduced thickness 100 at t~e ~oint i~ 3hown in Figure 2 as W. The maximum depth of the area of reduced thickness 100 i5 ghown in Figure 2 as X. The weldment joining together the abutting ~dge~ of the ring~ E and F will have the thickness Y. X plu~ Y equals the radial thickness Z of rin~s E and F. The thickne s Y, which equal~ the thickne~s of the weldm~nt (Figure 3) has a reduced thickne~ which i~ not g _ , more than about 0.90 of the rin~ thickness Z. ~owever, Y
i9 not les~ than 0.50 of Z. I~ i~ desirabl2 for the edges of the rings E, F to be tapered or curved outwardly from the thin~st portion Y of each ring to the thickest part o~
each ring Z. Thu~, a~ shown in Figures 2 and 3, each ring E, F i~ tapered outwardly 50, 52. As shown in Figure 2, the adjacent abuttin~ edges of rings E and F are beveled 36,38,40,42 to provide space for deposit of weld metal through the full thickness of the joint. Such beveled surface~ can have any suitable shape.
Returning now to Figure 2, the thickness Z of the rings used to fabricate shell 22 may be increased in thick-ness above the thlckne~s V used for rings where the joints are made the full thickness of the r.inys to reinforce the joint area surrounding the area of reduced thiclcnes~.
Thus, Z can be about 1 to 1.2 times the thickness V.
The second embodiment of the invention illus-trated by Figure 4 is similar to that shown in Figures 1 to
3~ Rings El and Fl in Figure 4 are comparable to rings E
and F in Figures 1 to 3. The embodiment of Figure 4, how-ever, will be seen to have the area of reduced thickness 100 on the inside of the shell rather than on the outside as shown in Figure~ 1 to 3.
The third embodiment of the invention is illus-trated by Figure 5. In this embodiment, an area of reduced thickness 102 is located radially inward from the outer surfase, and an area of reduced thicknes~ 104 i~ located radially outward from the inner surface of the rings E2, F2 of ~hell 22. It i9 to b~ understood that rings E2, F2 are like ring~ E, F and El, Fl ~xcept for the adjacent ~dge portions of reduced thickne3 ~.
~ 3~
Figure 6 illustrates the shell 22 fabricated as described in connection with Figures 1 to 3 but with each end open so that it can be used a~ a flow conductor, such as a p~n~tock, bla~t tube or for a similar purpose.
Exampl~
A pressure vessel is fabricated as illustrated by Figures 1 to 3 for a design pressure of 1800 p~ig and design temperature of 850F using SA-387, Grade 22, Class 2 steel. The vessel is de~igned to meet the code require-ments of ASME Section VIII, Division 2, para. AD-201. For an internal radius of 8 feet 8.5 inches, the thickness V of the rings A-J for full thickness weldments is 9 inches.
However, by utilization of the invention, the joint thick-ness Y can be reduced to 6 inches or less, with W equal to
and F in Figures 1 to 3. The embodiment of Figure 4, how-ever, will be seen to have the area of reduced thickness 100 on the inside of the shell rather than on the outside as shown in Figure~ 1 to 3.
The third embodiment of the invention is illus-trated by Figure 5. In this embodiment, an area of reduced thickness 102 is located radially inward from the outer surfase, and an area of reduced thicknes~ 104 i~ located radially outward from the inner surface of the rings E2, F2 of ~hell 22. It i9 to b~ understood that rings E2, F2 are like ring~ E, F and El, Fl ~xcept for the adjacent ~dge portions of reduced thickne3 ~.
~ 3~
Figure 6 illustrates the shell 22 fabricated as described in connection with Figures 1 to 3 but with each end open so that it can be used a~ a flow conductor, such as a p~n~tock, bla~t tube or for a similar purpose.
Exampl~
A pressure vessel is fabricated as illustrated by Figures 1 to 3 for a design pressure of 1800 p~ig and design temperature of 850F using SA-387, Grade 22, Class 2 steel. The vessel is de~igned to meet the code require-ments of ASME Section VIII, Division 2, para. AD-201. For an internal radius of 8 feet 8.5 inches, the thickness V of the rings A-J for full thickness weldments is 9 inches.
However, by utilization of the invention, the joint thick-ness Y can be reduced to 6 inches or less, with W equal to
4.5 inches. To provide some reinforcement about the joints, rings can be used with Z equal to more than 9 inches. For Z equal to 9.61", the extra thickness adjacent to the joint provides for full area replacement within the square root of the product of the radius and the thickness.
The final dimensions of Z and Y as well as the slope and location of the reduction levels 36,38,40,42 are to be determined by detailed stress analysis per the App~ndi~ 4 cri~eria o~ ~SME Section ~III, Di~ision 2 o~
other similar design proceduresO A variety of acceptable configurations can b~ provided. The actual configuration u~ilized will be determined by an overall ~ost analy~is of ~ 11 --the material cost~, shop labor and field labor for a particular structure.
The foregoing detailed description ha~ been given for clearness of under~tanding only, and no unnecessary limitation~ should be under~tood therefrom, as modifi-cation~ will be obvious to those ~killed in the art.
The final dimensions of Z and Y as well as the slope and location of the reduction levels 36,38,40,42 are to be determined by detailed stress analysis per the App~ndi~ 4 cri~eria o~ ~SME Section ~III, Di~ision 2 o~
other similar design proceduresO A variety of acceptable configurations can b~ provided. The actual configuration u~ilized will be determined by an overall ~ost analy~is of ~ 11 --the material cost~, shop labor and field labor for a particular structure.
The foregoing detailed description ha~ been given for clearness of under~tanding only, and no unnecessary limitation~ should be under~tood therefrom, as modifi-cation~ will be obvious to those ~killed in the art.
Claims (20)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. A circular cylindrical solid walled metal shell with inner and outer surfaces and being capable of withstanding an internal pressure for which the shell is designed;
the cylindrical shell comprising a series of consecutive metal rings of essentially equal maximum thick-ness positioned in axial arrangement with abutting ends of adjacent rings being joined together by a weldment; and with the axial length of the cylindrical shell portion comprising the abutting end portions of adjacent rings, and the weldment joining the abutting ends together, having a reduced thickness which is not more than about 0.90 of the maximum thickness of the rings.
the cylindrical shell comprising a series of consecutive metal rings of essentially equal maximum thick-ness positioned in axial arrangement with abutting ends of adjacent rings being joined together by a weldment; and with the axial length of the cylindrical shell portion comprising the abutting end portions of adjacent rings, and the weldment joining the abutting ends together, having a reduced thickness which is not more than about 0.90 of the maximum thickness of the rings.
2. A shell according to claim 1 in which the internal surface of the cylindrical shell is a sub-stantially smooth cylindrical surface at the weldment joining abutting ends of adjacent rings.
3. A shell according to claim 1 in which the external surface of the cylindrical shell is a substantial-ly smooth cylindrical surface at the weldment joining a-butting ends of adjacent rings.
4. A shell according to claim 1 in which:
the reduced thickness of the axial length of the cylindrical shell comprising the abutting end portions of adjacent rings is located radially inward from the outer surface of the shell and radially outward from the inner surface of the shell.
the reduced thickness of the axial length of the cylindrical shell comprising the abutting end portions of adjacent rings is located radially inward from the outer surface of the shell and radially outward from the inner surface of the shell.
5. A shell according to claim 1 in which the reduced thickness is not less than 0.50 of the maximum thickness of the rings.
6. A shell according to claim 1 in which the reduced thickness defines a peripheral groove extending around the outside of the vessel, with the groove having a maximum width axial of the vessel adequate to deposit at least a portion of the weldment from outside the shell.
7. A shell according to claim 1 in which the reduced thickness defines a peripheral groove extending around the inside of the vessel, with the groove having a maximum width axial of the vessel adequate to deposit at least a portion of the weldment from inside the shell.
8. A shell according to claim 1 in which the thickness of the rings is at least 3 inches.
9. A shell according to claim 1 in which the thickness of the rings is at least 1 inch.
10. A shell according to claim 1 in which the axial length of each ring is at least 2.5 times the square root of the cylindrical shell internal radius times the maximum thickness of the cylindrical shell.
11. A thick solid walled high-pressure vessel having a circular cylindrical shell with inner and outer surfaces and end closure and being capable of withstanding an internal pressure for which the vessel is designed;
the cylindrical shell comprising a series of consecutive metal rings of essentially equal maximum thick-ness positioned in axial arrangement with abutting ends of adjacent rings being joined together by a weldment; and with the axial length of the cylindrical shell portion comprising the abutting end portions of adjacent rings, and the weldment joining the abutting ends together, having a reduced thickness which is not more than about 0.90 of the maximum thickness of the rings.
the cylindrical shell comprising a series of consecutive metal rings of essentially equal maximum thick-ness positioned in axial arrangement with abutting ends of adjacent rings being joined together by a weldment; and with the axial length of the cylindrical shell portion comprising the abutting end portions of adjacent rings, and the weldment joining the abutting ends together, having a reduced thickness which is not more than about 0.90 of the maximum thickness of the rings.
12. A vessel according to claim 11 in which the internal surface of the cylindrical shell is a sub-stantially smooth cylindrical surface at the weldment joining abutting ends of adjacent rings.
13. A vessel according to claim 11 in which the external surface of the cylindrical shell is a substantial-ly smooth cylindrical surface at the weldment joining a-butting ends of adjacent rings.
14. A vessel according to claim 11 in which:
the reduced thickness of the axial length of the cylindrical shell is located radially inward from the outer surface of the shell and radially outward from the inner surface of the shell.
the reduced thickness of the axial length of the cylindrical shell is located radially inward from the outer surface of the shell and radially outward from the inner surface of the shell.
15. A vessel according to claim 11 in which the reduced thickness is not less than 0.50 of the maximum thickness of the rings.
16. A vessel according to claim 11 in which the area of reduced thickness defines a peripheral groove ex-tending around the outside of the vessel, with the groove having a maximum width axial of the vessel adequate to deposit at least a portion of the weldment from outside the shell.
17. A vessel according to claim 11 in which the area of reduced thickness defines a peripheral groove ex-tending around the inside of the vessel, with the groove having a maximum width axial of the vessel adequate to deposit at least a portion of the weldment from inside the shell.
18. A vessel according to claim 11 in which the thickness of the rings is at least 3 inches.
19. A vessel according to claim 11 in which the thickness of the rings is at least 1 inch .
20. A vessel according to claim 11 in which the axial length of each ring is at least 2.5 times the square root of the cylindrical shell internal radius times the maximum thickness of the cylindrical shell.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US06/875,462 US4724975A (en) | 1986-06-18 | 1986-06-18 | High-pressure structure made of rings with peripheral weldments of reduced thickness |
| US875,462 | 1986-06-18 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1272690A true CA1272690A (en) | 1990-08-14 |
Family
ID=25365850
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000523550A Expired - Lifetime CA1272690A (en) | 1986-06-18 | 1986-11-21 | High-pressure structure made of rings with peripheral weldments of reduced thickness |
Country Status (6)
| Country | Link |
|---|---|
| US (1) | US4724975A (en) |
| JP (1) | JPS631860A (en) |
| CA (1) | CA1272690A (en) |
| DE (1) | DE3639348C2 (en) |
| FR (1) | FR2600392A1 (en) |
| ZA (1) | ZA868954B (en) |
Families Citing this family (19)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5237981A (en) * | 1992-02-21 | 1993-08-24 | Pas, Inc. | Fuel injection apparatus for vehicles |
| US5429268A (en) * | 1993-03-05 | 1995-07-04 | Tri-Fuels, Inc. & The Rosalind Hale Revocable Trust | Tubular above ground gas storage vessel |
| US5908134A (en) * | 1993-03-05 | 1999-06-01 | The Rosalind Hale Revocable Trust, Uta George Carl Hale, Trustee | Tubular above ground gas storage vessel |
| US5697511A (en) * | 1996-09-27 | 1997-12-16 | Boeing North American, Inc. | Tank and method of fabrication |
| US6270045B1 (en) * | 1996-10-11 | 2001-08-07 | Kimball Physics, Inc. | Perimeter weld flanges |
| US6012598A (en) * | 1997-06-09 | 2000-01-11 | The Columbiana Boiler Company | Freight container |
| US7163121B1 (en) * | 1999-07-14 | 2007-01-16 | Swales & Associates, Inc. | High temperature isostatic pressure bonding of hollow beryllium pressure vessels using a bonding flange |
| US7024883B2 (en) * | 2003-12-19 | 2006-04-11 | Carrier Corporation | Vapor compression systems using an accumulator to prevent over-pressurization |
| US20080087665A1 (en) * | 2006-10-13 | 2008-04-17 | Columbiana Boiler Company, Llc | Freight container |
| CN100543349C (en) * | 2006-12-29 | 2009-09-23 | 陈阵 | Multiunit tube joint and processing method thereof |
| DE212009000005U1 (en) * | 2009-09-22 | 2010-02-11 | Faber Industrie S.P.A., Cividale Del Friuli | gas bottle |
| CN101934420A (en) * | 2010-08-18 | 2011-01-05 | 中信重工机械股份有限公司 | Method for welding conical mill |
| SE535989C2 (en) * | 2011-03-23 | 2013-03-19 | Northcone Ab | Compliant post and way of arranging road lighting |
| WO2012164701A1 (en) * | 2011-06-01 | 2012-12-06 | トヨタ自動車株式会社 | Welded joint structure and weld quality detection method |
| FR2992880B1 (en) * | 2012-07-06 | 2015-02-13 | Snecma | PIECE FOR FRICTION WELDING |
| GB201413923D0 (en) * | 2014-08-06 | 2014-09-17 | Rolls Royce Plc | Rotary friction welding |
| JP6449749B2 (en) * | 2015-10-19 | 2019-01-09 | 株式会社神戸製鋼所 | Radioactive material transport storage container and method for manufacturing radioactive material transport storage container |
| CN108599063B (en) * | 2018-05-21 | 2024-01-05 | 深圳市沃尔核材股份有限公司 | Connection method and connection structure of two tubular buses for wind power tower |
| KR102615646B1 (en) * | 2022-01-28 | 2023-12-19 | 삼성엔지니어링 주식회사 | Weld groove forming method and hollow article |
Family Cites Families (12)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US1655931A (en) * | 1926-03-13 | 1928-01-10 | Smith Corp A O | Oil-refining still and method of making the same by electric-arc welding |
| US1961117A (en) * | 1932-06-04 | 1934-05-29 | Linde Air Prod Co | Method of welding copper alloys, particularly wrought copper alloys |
| CH166852A (en) * | 1933-02-10 | 1934-01-31 | Buss Ag | Process to reduce the strength of the V and X butt welds on circumferential seams of hollow bodies. |
| US2179774A (en) * | 1935-12-07 | 1939-11-14 | Smith Corp A O | Welded pressure vessel |
| US2233455A (en) * | 1938-05-21 | 1941-03-04 | Smith Corp A O | Method of welding |
| US2391747A (en) * | 1942-08-26 | 1945-12-25 | Babcock & Wilcox Co | Penstock and method of fabricating penstocks |
| US3270906A (en) * | 1963-09-25 | 1966-09-06 | Chemical Construction Corp | Closure for pressure vessels |
| GB1253250A (en) * | 1968-09-24 | 1971-11-10 | ||
| JPS4827215U (en) * | 1971-08-05 | 1973-04-02 | ||
| JPS5118950A (en) * | 1974-08-07 | 1976-02-14 | Babcock Hitachi Kk | Enshinchuzokanno tsukiawaseyosetsuhoho |
| JPS5572977A (en) * | 1978-11-28 | 1980-06-02 | Babcock Hitachi Kk | Welded joint structure of centrifugal casted pipe |
| DE3507010A1 (en) * | 1985-02-28 | 1986-08-28 | Fa. Eisenbau Krämer mbH, 5912 Hilchenbach | Method for the production of, in particular, thick-walled tubes |
-
1986
- 1986-06-18 US US06/875,462 patent/US4724975A/en not_active Expired - Lifetime
- 1986-11-18 DE DE3639348A patent/DE3639348C2/en not_active Expired - Fee Related
- 1986-11-21 CA CA000523550A patent/CA1272690A/en not_active Expired - Lifetime
- 1986-11-26 ZA ZA868954A patent/ZA868954B/en unknown
- 1986-12-03 FR FR8616916A patent/FR2600392A1/en active Pending
- 1986-12-11 JP JP61295711A patent/JPS631860A/en active Pending
Also Published As
| Publication number | Publication date |
|---|---|
| ZA868954B (en) | 1987-08-26 |
| JPS631860A (en) | 1988-01-06 |
| DE3639348A1 (en) | 1987-12-23 |
| FR2600392A1 (en) | 1987-12-24 |
| US4724975A (en) | 1988-02-16 |
| DE3639348C2 (en) | 1998-12-10 |
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